| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a sintering apparatus and a sintering method for a glass preform which can suppress transmission loss of an optical fiber by controlling adhesion of impurities to the glass preform. <P>SOLUTION: In the sintering apparatus 10, a distributor 20 whose size is 50-90% of the virtual cross-sectional area SO of a furnace core tube 11 having an inside diameter DO is disposed above a glass fine particle deposited body 14. A prescribed amount of an inert gas G is introduced from a gas supply part 17 in the lower portion of the furnace core tube 11 so that an average flow velocity V of the inert gas G flowing upward from beneath in the gap between the outer circumferential edge 27 of the distributor 20 and the inner wall 28 of the furnace core tube 11 may become≥55 mm/s, and the unnecessary gas is exhausted from a gas exhaust part 18 in the upper portion of the furnace core tube 11. The distance H between the under surface of the distributor 20 and the top edge of the glass fine particle deposited body 14 is confined to≤400 mm. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
